In some of the known sofa-beds of the above mentioned type, it is necessary that the sofa-bed seat/back assembly be manually rotated with respect to the base thererof, until an unlocking mechanism in the back and seat hinge be actuated for the seat/back assembly to become an horizontal surface on which the user may lie in the longitudinal extension of the sofa-bed This type of construction requires a considerable physical exertion from the user in order to configure a bed from a sofa-configuration.
Still in that solution, the crease defined between the back and seat does not allow the surface thereof to be entirely flat after configuring the bed, thereby causing the user, on laying down, to roll towards said crease, which renders the bed thus configured quite inadequate in terms of comfort, also poorly stable by reason of the lateral shifts of the back and the seat in respect of the sofa-bed base.
Besides frequently requiring displacement of the sofa-bed with respect to an adjacent wall before configuring the bed, this known solution requires the sofa-bed length to be equal to that of a bed. Another type of known sofa-bed comprises a hollow sofa structure provided with removable seat and back cushions, the inside of said structure being provided and hinged with a conventional foldable bed. In this solution, the individual sofa and bed structures are heavy, the bed assembly still requires a substantial operational physical effort, plus the fact that, for unfolding and assembly of the bed, it is necessary to remove the sofa-bed back and seat cushions. Finally, in any of the above described solutions, should the user wish to read, write or even watch TV while lying on the bed, it will be necessary to pile up cushions or pillows in order to reach a comfortable position.